MB-100 make ep-engine compile

Change-Id: I72a1c766415c1e458d625f4d1f58fa56048ed10d
Reviewed-on: http://review.couchbase.org/27521
Reviewed-by: Chiyoung Seo <chiyoung.seo@gmail.com>
Tested-by: Chiyoung Seo <chiyoung.seo@gmail.com>